A light emitting device utilizing light emitted from an electroluminescent element (a light emitting element) has wide-viewing angle and low power consumption. In recent years, research and development of a light emitting device, which can provide high quality images for the long term, have been carried out actively in the development area of light emitting devices so as to dominate the market for display devices that are applied to various kinds of information processing devices such as a television receiver and a car navigation system.
In order to obtain a light emitting device, which can provide high quality images for the long term, development of a long-life light emitting element and a light emitting element that emits light efficiently becomes important.
For example, the patent document 1 discloses a technique related to a light emitting element with a plurality of light emitting units in which the respective light emitting units are separated by a charge generating layer. The patent document 1 describes a long-life light emitting element with high luminance. However, vanadium pentoxide used in the patent document 1 has a high moisture absorbing property. Therefore, the light emitting element is possibly deteriorated due to moisture absorbed by vanadium pentoxide. The deterioration of the light emitting element results in deterioration of image quality in a light emitting device.
Accordingly, in the development of light emitting devices, it is also important to manufacture a light emitting element having a high moisture resistant property along with high luminance.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2003-272860.